The invention relates to a method for the operation of a navigation device, and to a navigation device.
Navigation devices are used in modern motor vehicles with increasing frequency. They enable determination of a route between a starting point and an ending point, and enable regular route guidance to a destination by utilizing updated position data, which is regularly collected by means of a GPS system.
Navigation devices are also equipped with a communication interface with increasing frequency. The interface enables communication with an external computer. In this case, communication takes place via a cellular or wireless radio interface and a corresponding cellular or wireless radio network, wherein the latter can be connected to the Internet. Such a navigation system, which also comprises an external computer in addition to the navigation device and the communication interface which is functionally assigned to the same, makes it possible to transmit a route, represented by route elements, to the navigation device, wherein the route is then utilized for the purpose of route guidance, by way of example. In order to transmit the required information about the route in the most efficient manner possible, data reduction is preferably carried out on multiple route elements which characterize the route in the clearest manner possible.
Each of the route elements can then be utilized in the navigation device to reconstruct the route and then to provide route guidance from the starting point to the prespecified destination.
The problem addressed by the invention is that of creating a method for the operation of a navigation device, and a navigation device, wherein the same enable user-friendly operation of the navigation device.
According to a first aspect of the invention, a method is provided for the operation of a navigation device. According to a second aspect of the invention, a navigation device is provided which is designed for carrying out the method, and optionally also for carrying out an advantageous embodiment of the method.
Multiple route elements, which each comprise at least one parameter, are provided in the navigation device. The route elements characterize a route. By way of example, the route elements can include waypoints. Each of the route elements are functionally assigned to local route elements which are saved on a digital memory is stored in the navigation device. A quality coefficient for the assignability to a local route element is determined for each of the route elements depending on at least one of the at least one parameters. The locally assigned route elements can be utilized to reconstruct the route, which can in turn be used as the basis for route guidance. As such, the route which is characterized by the route elements can fundamentally deviate from the route reconstructed by way of the assigned local route elements.
The reason for this can be the particularly differing degrees to which the digital memory card in the navigation device and the particularly external digital memory card are updated. The external memory card is functionally assigned to the route elements provided in the device. As such, depending on how updated the cards are, for example, different road courses may be present, streets may be added or disappear, or street names may change, for example.
A quality coefficient is determined for each of the route elements for the assignability thereof to a local route element depending on at least one of the at least one parameters. In this way, the quality coefficient is representative of a correlation between each route element and a local route element to which it is assigned.
A quality coefficient for the route reconstruction is determined depending on each of the quality coefficients of the route elements. In this way, information is available which is representative of a correlation between the route and a route which is reconstructed by way of the local route elements. This enables particularly user-friendly operation of the navigation device. By way of example, the route reconstruction quality coefficient can be output in a suitable manner, for example visually and/or acoustically.
In this way, the device can also advantageously output information indicating that the route cannot be reconstructed, if the route reconstruction quality coefficient falls below a prespecified reconstruction threshold. The user can then have the option, for example, of rejecting the route, or using the route for route guidance despite a certain uncertainty in the route guidance.
It is preferred that, if a higher value of the route reconstruction coefficient is representative of a high degree of correlation between the route and the route which is reconstructed by way of the assigned local route elements, the device outputs that the route cannot be reconstructed if the route reconstruction quality coefficient falls below the reconstruction threshold. If, on the other hand, a high value of the route reconstruction quality coefficient is representative of a low degree of correlation between the route and the route which is reconstructed by way of the assigned local route elements, the device outputs that the route cannot be reconstructed if the route reconstruction quality coefficient exceeds the reconstruction threshold.
As such, depending on the form of the data contained in the route reconstruction quality coefficient, the output of the device indicates that the route cannot be reconstructed. In one case this occurs if the coefficient falls below the reconstruction threshold, and in the other case it occurs if the reconstruction threshold is exceeded.
According to a further advantageous embodiment, a parameter quality coefficient is determined for each of the parameters of each of the route elements, and this coefficient characterizes the assignability of each of the parameters to a corresponding parameter of the respective assigned local route element. The quality coefficient for each of the route elements is then determined depending on the parameter quality coefficient.
In this way, the quality coefficient for each of the route elements can be determined in a particularly simple and precise manner.
According to a further advantageous embodiment, the parameter quality coefficients are each weighted with prespecified weighting factors for the purpose of determining the quality coefficient. In this way, the method can incorporate a suitable valuation of the individual parameter quality coefficients in a simple manner when determining the quality coefficient, and thereby determine the quality coefficient in a particularly precise manner.
According to a further advantageous embodiment, for the purpose of determining the route reconstruction quality coefficient, the quality coefficients of the route elements are weighted depending on a distance variable, wherein the distance variable is representative of a distance to the geographically proximate route element. In this way, by means of accordingly specifying the respective distance variable, the influence of quality coefficients on the route reconstruction quality coefficient, in a situation where route elements are located in close proximity to each other, for example, can be kept to a minimum.
This implementation utilizes the knowledge that when route elements are located in close proximity to each other, and a quality coefficient is used which is representative of a low correlation, the influence on the correlation between the reconstructed route and the route is relatively small.
It is also particularly advantageous if the reconstruction threshold can be prespecified by user input. In this manner, the user can control when the device outputs that a route could not be reconstructed.
The parameter is preferably characteristic of a geographical coordinate (geo-coordinate), a street name, a direction of travel, a geodetic height, a type of street, a number of road lanes, an orientation with respect to a prespecified direction on the compass, an allowed or average speed on a road, and/or a structural division of a road.
When multiple parameters are assigned to a route element, the individual parameters are then characteristic of one of each of the listed possible characteristics. As such, each route element can have as the parameter, for example, a first parameter which is characteristic of a geo-coordinate, a second parameter which is characteristic of a street name, and by way of example, a third parameter which is characteristic of geodetic height. Particularly by means of providing multiple parameters, assignment can be made with higher probability to an actually suitable local route element.
Each route element can represent, by way of example, a waypoint or a line connecting two waypoints.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.